1. Field of the Invention
The present invention generally relates to a method for forming semiconductor devices. More specifically, the present invention relates to a method for forming individual semiconductor devices including micro-mechanical elements formed on a semiconductor substrate, also known as MEMS (Micro Electro Mechanical System) chips.
2. Background Information
MEMS is a system by which very small micro-mechanical elements and electronic circuits are integrated on a semiconductor substrate by using ultra-fine processing technology for the semiconductor. MEMS chips are mechanically cut by a diamond cutter when they are separated into individual chips, in a process that is generally similar to those of typical semiconductor devices.
A method for forming individual semiconductor devices is disclosed in Japanese Laid-Open Patent Publication TOKUKAI No. JP2001-144035 (especially page 3-4, FIGS. 1 and 2), for example, the entire disclosure of which is hereby incorporated by reference. The method for forming individual semiconductor devices disclosed in JP2001-144035 in the WCSP (WaferLevel Chip Size Package) semiconductor device in which package molding is performed while in a wafer state includes two steps; a first step of cutting only molding resin, and a second step of cutting a semiconductor substrate. The first step of cutting the molding resin is performed in a non-contact processing manner by using a laser, for example. The second step of cutting the semiconductor substrate is performed in a contact processing manner by using a mechanical cutting tool such as a diamond cutter. Cutting the molding resin in a non-contact processing manner can suppress the peeling-off of molding resin due to external forces in the cutting, and it is possible to form individual semiconductor devices with high quality.
Since a mechanical element included in an MEMS chip is very fragile with regards to external vibration and impact, in a dicing process where individual MEMSs are formed, the mechanical elements are easily damaged due to the mechanical vibration or impact from cleaning water spray.
In the method for forming individual semiconductor devices disclosed in JP2001-144035, a contact processing using a mechanical cutting tool is performed on the semiconductor substrate in the second step. Accordingly, it is inevitable that vibrations or an impact occurs when cutting. For this reason, it is not preferable that this method for manufacturing be applied to a dicing process for MEMS.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved a method for forming individual semiconductor devices. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.